# What might have happened to \*my\* @code\_warntype?

**URL:** <https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435>\
**Category:** General Usage\
**Created:** [February 17, 2021, 2:27am UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435 "2021-02-17T02:27:19Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [February 17, 2021, 2:27am UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/1 "2021-02-17T02:27:19Z")

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I run this command many times before and it used to print hundreds of lines, now it just print this (same for other `@code_warntype` calls to other functions)

```julia
julia> @code_warntype plot([0 0; 1 1]);
Variables
  #self#::Core.Const(GMT.plot)
  arg1::Matrix{Int64}

Body::Any
1 ─ %1 = Core.NamedTuple()::Core.Const(NamedTuple())
│ %2 = Base.pairs(%1)::Core.Const(Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}())
│ %3 = GMT.:(var"#plot#228")(true, %2, #self#, arg1)::Any
└── return %3

```

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**Author:** ![mmiller](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmiller/32/20805_2.png) [@mmiller](https://discourse.julialang.org/u/mmiller)\
**Post date:** [February 17, 2021, 8:14am UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/2 "2021-02-17T08:14:07Z")

</div>

Hopefully someone who knows more can help with this, but I’ve seen this happen when the functions I’m using `@code_warntype` on have keyword arguments:

```nohighlight
function f1(a; b=2,c=3)
    a*b
    d = zeros(b, c*4)
end

```

```nohighlight
julia> @code_warntype f1(1)
Variables
  #self#::Core.Compiler.Const(f1, false)
  a::Int64

Body::Array{Float64,2}
1 ─ %1 = Main.:(var"#f1#10")(2, 3, #self#, a)::Array{Float64,2}
└── return %1

```

If I add the kwargs when using `@code_warntype` I get more output:

```julia
julia> @code_warntype f1(1;b=2,c=3)
Variables
  #unused#::Core.Compiler.Const(var"#f1##kw"(), false)
  @_2::NamedTuple{(:b, :c),Tuple{Int64,Int64}}
  @_3::Core.Compiler.Const(f1, false)
  a::Int64
  b::Int64
  c::Int64
  @_7::Int64
  @_8::Int64

Body::Array{Float64,2}
1 ─ %1 = Base.haskey(@_2, :b)::Core.Compiler.Const(true, false)
│ %1
│ (@_7 = Base.getindex(@_2, :b))
└── goto #3
2 ─ Core.Compiler.Const(:(@_7 = 2), false)
3 ┄ (b = @_7)
│ %7 = Base.haskey(@_2, :c)::Core.Compiler.Const(true, false)
│ %7
│ (@_8 = Base.getindex(@_2, :c))
└── goto #5
4 ─ Core.Compiler.Const(:(@_8 = 3), false)
5 ┄ (c = @_8)
│ %13 = (:b, :c)::Core.Compiler.Const((:b, :c), false)
│ %14 = Core.apply_type(Core.NamedTuple, %13)::Core.Compiler.Const(NamedTuple{(:b, :c),T} where T<:Tuple, false)
│ %15 = Base.structdiff(@_2, %14)::Core.Compiler.Const(NamedTuple(), false)
│ %16 = Base.pairs(%15)::Core.Compiler.Const(Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}(), false)
│ %17 = Base.isempty(%16)::Core.Compiler.Const(true, false)
│ %17
└── goto #7
6 ─ Core.Compiler.Const(:(Base.kwerr(@_2, @_3, a)), false)
7 ┄ %21 = Main.:(var"#f1#10")(b, c, @_3, a)::Array{Float64,2}
└── return %21

```

---

<div class="post-metadata">

**Author:** ![thofma](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/thofma/32/1691_2.png) [@thofma](https://discourse.julialang.org/u/thofma)\
**Post date:** [February 17, 2021, 9:19am UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/3 "2021-02-17T09:19:38Z")

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To supplement what @mmiller said, if you define a function with keyword arguments, this gets ‘translated’ into an outer function dealing with the keyword arguments (the one you see), and some internal function which basically contains the body of your original function. In your example the function call you would want to see is

```julia
  %3 = GMT.:(var"#plot#228")(true, %2, #self#, arg1)::Any

```

To do `@code_warntype` on this, I recommend the use of [GitHub - JuliaDebug/Cthulhu.jl: The slow descent into madness](https://github.com/JuliaDebug/Cthulhu.jl), which allows you to easily navigate to the function you really care about (once you are inside `@descend`, type `w` to toggle colors for warnings and `o` to toggle optimizations).

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<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [February 17, 2021, 3:28pm UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/4 "2021-02-17T15:28:04Z")

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Thanks, you’re right. Consulting my `repl_history.jl` I found that the (very) long output is obtained when I call the function that does the work

```julia
@code_warntype GMT.common_plot_xyz("", [0.0 0.0; 1.0 1.0], "", true, false)

```

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<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [February 17, 2021, 3:31pm UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/5 "2021-02-17T15:31:39Z")

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I have tried to use `Cthulhu` before, but for this example I just fall into a dead-end and cannot get inside the function of interests

```julia
# If I enter in %3 (which what I want)
Actions: [E]dit source code, [R]evise and redisplay
Advanced: dump [P]arams cache.
   %1 = NamedTuple()::Core.Const(NamedTuple())
   %2 = pairs(::NamedTuple{(), Tuple{}})::Core.Const(Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}}())
 • %3 = #plot#228(::Bool,::Base.Iterators.Pairs{Union{}, Union{}, Tuple{}, NamedTuple{(), Tuple{}}},::typeof(plot),::Matrix{Int64})::Any

```

I land in

```julia
Show: [S]ource code, [A]ST, [L]LVM IR, [N]ative code
Actions: [E]dit source code, [R]evise and redisplay
Advanced: dump [P]arams cache.
 • %2 = cat_1_arg(::Matrix{Int64})::Matrix{Int64}

```

from which I can’t do nothing but come back to previous step

```julia
Select a call to descend into or ↩ to ascend. [q]uit. [b]ookmark.
Toggles: [o]ptimize, [w]arn, [v]erbose printing for warntype code, [d]ebuginfo, [s]yntax highlight for Source/LLVM/Native.
Show: [S]ource code, [A]ST, [L]LVM IR, [N]ative code
Actions: [E]dit source code, [R]evise and redisplay
Advanced: dump [P]arams cache.

```

---

<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [February 17, 2021, 3:54pm UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/6 "2021-02-17T15:54:29Z")

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On a side note to this. I can’t understand how the return type of the `length` or `string` functions can by a **Any**

```julia
163 ─ %728 = GMT.string(val)::Any
or
%207 = GMT.length(gval)::Any

```

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<div class="post-metadata">

**Author:** ![thofma](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/thofma/32/1691_2.png) [@thofma](https://discourse.julialang.org/u/thofma)\
**Post date:** [February 17, 2021, 3:58pm UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/7 "2021-02-17T15:58:52Z")

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I can reproduce it. Might be a good idea to open an issue.

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<div class="post-metadata">

**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [February 17, 2021, 4:04pm UTC](https://discourse.julialang.org/t/what-might-have-happened-to-my-code-warntype/55435/8 "2021-02-17T16:04:21Z")

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Ok, but let’s bother (sorry) @tim.holy first. He may have an explanation saying _Sorry, that’s how it works_